<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>标签选择器</title>
    <!--
        1:id选择器使用#
        2：类选择器使用.
    -->
    <style>
        ol{
            color: red;
        }
        ol #i1{
            color: aqua;
        }
        ul{
            color: green;
        }
        ul .c1{
            color: plum;
        }
    </style>
</head>
<body>
    <ol>
        <li>windows</li>
        <li id="i1">Linux</li>
        <li>MacOS</li>
    </ol>
    <ul>
        <li>HTML</li>
        <li class="c1">JAVA</li>
        <li>BigData</li>
    </ul>
</body>
</html>